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Liu F.,Chongqing Medical University | Xiang G.,Chongqing Medical University | Chen X.,Shima River Community Health Center | Luo F.,Chongqing Medical University | And 4 more authors.
RSC Advances | Year: 2014

Procalcitonin (PCT) is a common clinical biomarker of septicemia, and precise detection of PCT is critical to the treatment of septicemia. Conventional detection methods suffer various shortcomings that hinder precise PCT detection. An electrochemical immunosensor based on the antigen-antibody immune-reaction may provide a solution. We developed a novel electrochemical immunosensor for PCT using single-walled carbon nanohorns (SWCNHs)-hollow Pt nanospheres (HPtNPs) as signal tags. Given the high specific surface area of SWCNHs and the interesting catalytic properties of HPtNPs, the successful synthesis of SWCNHs-HPtNPs provided not only a high specific surface area for loading substantial antigen but also good catalytic properties to enhance the electrochemical signal with high sensitivity. In addition, to increase the quantity of the electrochemically active compound thionine immobilized on the surface, PAMAM, which is a class of hyper-branched polymers with a diamine core and an amido amine branching structure, was assembled on the SWCNH-HPtNP surface. A series of results demonstrated the higher sensitivity, improved stability and ideal selectivity of the novel immunosensor compared with a sensor prepared using traditional methods. Furthermore, a broad linear response from 10 pg mL-1 to 20 ng mL-1 with a detection limit of 1.74 pg mL-1 was observed under the optimized conditions of the assay. This immunosensor may provide a new option for clinical septicemia diagnosis through PCT detection. © 2014 The Royal Society of Chemistry. Source

Liu F.,Chongqing Medical University | Xiang G.,Chongqing Medical University | Jiang D.,Chongqing Medical University | Zhang L.,Chongqing Medical University | And 6 more authors.
Biosensors and Bioelectronics | Year: 2015

Highly up-regulated in liver cancer (HULC) is a novel promising noninvasive biomarker for hepatocellular carcinoma (HCC), which is a kind of long non-coding RNAs (lncRNAs). But traditional methods limited HULC clinical detection for ownself drawbacks. Development a new HULC detection approach is urgent and necessary. Electrochemical nucleic acid sensor based on different signal amplification strategies with high sensitivity, fast, simple, and convenient, may solve this problem. Herein, we propose a novel strategy based on Pt-Pd bimetallic nanodendrites/nanoflower-like clusters on graphene oxide/Au/horseradish peroxidase (PtPd BND/BNF@GO/Au/HRP) to enhance the catalytic efficiency and sensitivity. And Au particles were simultaneously and separately capped with thionine or detection probe, which increase the binding amount of detection probe and decrease the electronic background. The results indicated that the catalytic effect was noticeably elevated and that the biosensor provides ultrasensitive detection for the lncRNA HULC. The linear calibration of the biosensor ranged from 1.00×10-3 to 1.00×103pM/mL, and the limit of detection was 0.247fM/mL. The lncRNA biosensor based on the PtPd BND/BNF@GO/Au/HRP/Au/thionine exhibited acceptable reproducibility and clear selectivity. This strategy may provide a new alternative for clinical HCC diagnosis through the detection of HULC. © 2015 Elsevier B.V. Source

Liu F.,Chongqing Medical University | Xiang G.,Chongqing Medical University | Yuan R.,Southwest University | Chen X.,Shima River Community Health Center | And 5 more authors.
Biosensors and Bioelectronics | Year: 2014

Septicemia is a serious disease that requires early diagnosis, and procalcitonin (PCT) serves as a diagnostic biomarker for this disease. Traditional clinical detection (via immune-gold chips) remains difficult and expensive. An electrochemical immunosensor based on new nanomaterials may provide a solving approach. Herein, an ultrasensitive sandwich electrochemical strategy for PCT detection was developed. Firstly, reduced graphene oxide (rGO)-gold (Au) nano-composite film was used as the immunosensor platform to increase the amount of PCT antibody 1(Ab1) immobilized. Next, single-walled carbon nanohorns (SWCNHs)/hollow Pt chains (HPtCs) complex was firstly utilized to label PCT Ab2 as signal tags. For SWCNHs with few side effects, high surface area and HPtCs with higher specific surface, better catalytic activity, complex synthesized from both may provide more advantages. Moreover, to amplify signal, HPtC catalytic activity with H2O2 was enhanced by horseradish peroxidase (HRP) for dual synergy amplification. The whole results demonstrated that the proposed immunosensor exhibited fast operation, high sensitivity, good reproducibility, acceptable stability and ideal selectivity compared with traditional method. The linear calibration of the immunosensor ranged from 1.00pg/mL to 2.00×101ng/mL with a detection limit of 0.43pg/mL. Analytical application results revealed that the immunosensor matched with the real concentrations of serum samples. Overall this immunosensor may provide a new alternative strategy for PCT detection. © 2014 Elsevier B.V. Source

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